In Oban, the price of diesel reached $4, and 91 octane reached $4.07 on the Gaspy app yesterday.
Southland district councillor and Stewart Island resident Jon Spraggon said residents were now really starting to feel the pinch.
‘‘All our power is generated with a diesel generator, so I suspect power prices will possibly skyrocket.
‘‘It's not only the cost of electricity, it's the cost of getting groceries and everything to the island.
‘‘And it's not only getting it to the island, it's the cost on the mainland of getting it to Invercargill and to Bluff - the cost of transport.
‘‘Yeah, so the islanders are feeling the pinch.’’
He said it may only be a matter of time before the price of fuel on the mainland also breaks the $4 barrier.
‘‘If it goes that high in the South Island, it means we'll go higher still.’’
Despite the fuel price hikes, he believed Stewart Islanders were ‘‘resilient’’ and would overcome the challenges.
Rakiura Adventure Ltd operations manager Rakiura Herzhoff said living on the island had always been expensive, but things were getting tough for businesses.
Mr Herzhoff said he used four boats to ferry tourists around the sites and tracks of the island - two of the boats ran on petrol and the other two on diesel.
‘‘It does make things more difficult.
‘‘My attitude to it is, we have to honour the bookings that we already have at the price that we have, but if the trend doesn't progress to normal pricing for the fuel, then we will have to amend our prices for the next season.’’
He said life on the island was more challenging, especially for families with children, and even more so for those with children at boarding school on the mainland.
‘‘Who knows if the cost of the ferry or the planes will go up. Who knows if they'll be able to maintain a good local rate for those families.
"Nothing will be easy. But we're very resilient people - that’s the reason why we're here. We will adapt.
‘‘It's just the nature of who we are.’’
He said many islanders would just stay at home and try to save money during the winter ‘‘off season’’, rather than go on holiday.
Some would probably also get a part-time job on the island, if there were any available.
Gaspy spokesman Mike Newton said diesel was normally expected to be 70c cheaper than 91 nationally because of petrol tax, but it was now only about 20c cheaper.
‘‘Diesel drivers are definitely getting it worse because they’ve still got to pay their road user charges.’’
Diesel is more expensive to make than petrol, but the impact of fuel excise tax usually conceals this.
Transporting New Zealand head of policy and advocacy Billy Clemens said diesel was usually the second-largest cost for its member businesses, after wages.
‘‘It’s a cost that sits typically around 15%-20% of overall costs. And road freight’s pretty famously a pretty low-margin game.
‘‘So our members are in a position whether they can either pass those costs on or end up in a really difficult position with their business viability.’’
He said about half the organisation’s members were likely to be using a fuel adjustment factor.
‘‘That’s a sizable cost on businesses right across the country, whether you’re in retail or construction or logging — there’ll be a real flow-on impact.’’
Mr Clemens said shortages were not widespread and seemed to be driven by demand patterns.
Associate Minister for Energy Shane Jones said the government was taking practical steps to strengthen New Zealand’s fuel resilience, by temporarily allowing fuel that meets Australian specifications to be supplied to the New Zealand market.
‘‘This decision removes unnecessary technical barriers and helps ensure New Zealand isn’t excluded from available supply our neighbours across the Tasman are accessing.’’
Fuel specifications differ for the purpose of catering to different climate conditions.
For example, diesel for hot climates could not be sold in very cold ones.
However, fuel refined to Australian standards would still be compatible with New Zealand vehicles and meet safety and quality expectations.
‘‘Fuel companies have told us this could allow them to secure shipments more quickly and from a wider pool of suppliers.
‘‘We are closely monitoring market conditions and will keep under review any further practical measures that could strengthen New Zealand’s fuel supply resilience while global conditions remain uncertain.’’
The temporary alignment with Australian specifications could remain in place for up to 12 months if needed, he said.
— Additional reporting RNZ
